is the OA (C)?
(1) y^2=z.x
if y=4, z=16, then x=1. so, y>x
if y=4, z=1, then x=16. so, y<x
insufficient.
(2) no info about y. insufficient.
(1) & (2):
from (2) we know that z>x
let us assume, for a moment, that z=x, which is the maximum value possible.
then y=z=x (from st. 1)
but actually x<z. so x<y
sufficient.
integers
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Source: Beat The GMAT — Data Sufficiency |
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Musiq
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Is Y >X ?ketkoag wrote:If X, Y, and Z are positive integers, is Y>X?
(1) Y^2=XZ
(2) Z-X>0
i got this ques correct but i did it by assuming the values, could any one tell me is there any better way to do solve this.
Statement II:
No information about Y....so Insufficient...but restate the statement for further use ( if necessary)
Z - X > 0
Or, Z > X
Statement I:
(Y) (Y) = (X) ( Z)
For Y to be greater than X, we need to knwo more about Z.....but we dont.
Combining:
(Y) (Y) = (X) ( A number greater than X)
oR, (Y) ^2 = A number greater than (X) ^2
Since we are only asked to consider positive integers, this necessarily simplifies to Y > X.
Answer = C
NOTE:
I showed this explanation because you asked for a mathematical explanation....but Picking Number is the not a bad alternative method to use here.
For love, not money.
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kanha81
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(1) Y^2=XZketkoag wrote:If X, Y, and Z are positive integers, is Y>X?
(1) Y^2=XZ
(2) Z-X>0
i got this ques correct but i did it by assuming the values, could any one tell me is there any better way to do solve this.
No inform. abt relationship among x, y, z
Insuff
(2) Z-X>0
=> z > x
No inform. about y
(1) & (2)-
z = y^2 / x
((y^2) / x) > x
(y^2) > (x^2)
y > +/- x, but x>0
y > x
Suff
[spoiler][C][/spoiler]
Want to Beat GMAT.
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